<!DOCTYPE HTML>
<html>
<head>
  <title>反ajax推送</title>
  <style>
    .send{color:#555;text-align: left;}
    .require{color:blue;text-align: right;}
    .content_box{text-align: center;margin: 20px;
      border: 1px solid #ddd;padding: 20px;}
  </style>
  <script src="http://code.jQuery.com/jquery-1.11.2.min.js"></script>
</head>
<body>
<div class="content_box" id="content_box_title" style="border: none;">消息框</div>
<div class="content_box" id="content_box">
</div>
<div style="width: 467px;margin: 0 auto;">
  <select id="username" style="font-size: 20px;">
    <option value="1" selected="selected">用户1</option>
    <option value="2">用户2</option>
  </select>
  <input type="text" style="font-size: 20px;" value="" id="send_text">
  <button id="btn_send" style="font-size: 20px;">发送</button>
  <button id="btn_link" style="font-size: 20px">连接</button>
</div>
<div class="error_tip" id="error_tip" style="color: red;">
</div>
<script>
    $(function(){
        //发送消息
        $('#btn_send').click(function(){
            var send_text = $('#send_text').val();
            if(send_text.length <= 0){
                $('#error_tip').html('不能输入空值');
            }else{
                send(send_text);
            }
        });
        //按回车键发送消息
        $('#send_text').on('keyup',function(e){
            if(e.keyCode === 13){
                $('#btn_send').trigger('click');
            }
        });
        //建立通讯链接
        $('#btn_link').click(function(){
            connect();
            var _this = $(this);
            _this.attr('disabled',true);
            _this.html('已连接');
        });
    });
    //建立通讯连接函数
    function connect(){
        $('#content_box_title').html($('#username').val()+'的消息窗口');
        $.ajax({
            data:{'user':$('#username').val()},
            url:'/index/Long/push',
            type:'get',
            timeout:0,
            dataType:'json',
            success:function(data){
                $('#content_box').append('<div class="require">'+data.msg+'</div>');
                connect();
            }
        });
    }
    //发送消息函数
    function send(massege){
        var user =$('#username').val();
        $.getJSON('/index/Long/write',{'msg':massege,'user':user},function(data){
            if(data.sf){
                $('#content_box').append('<div class="send">'+massege+'</div>');
                $('#send_text').val('');
            }else{
                $('#error_tip').html('输入保存错误！');
            }
        });
    }
</script>
</body>
</html>

